Emulsion polymerization of styrene: double emulsion effect

Lin, Shi‐Yow; Chern, Chorng–Shyan; Hsu, Tien-Jung; Hsu, Ching-Tien; Capek, Ignác

doi:10.1016/s0032-3861(00)00526-7

Cited by 19 publications

(14 citation statements)

References 28 publications

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“…With increasing the emulsifier concentration also increases the initiator concentration. The present behavior is similar to that reported for the sterically-stabilized emulsion, miniemulsion and microemulsion polymerizations of styrene and other unsaturated monomers initiated by peroxodisulfate [12,28,[31][32][33]. In those works the particle number increased strongly with increasing the emulsifier concentration, that is, the reaction order x of the dependence of N p vs [Tw] x was much above 1.0.…”

Section: Rate Of Polymerizationsupporting

confidence: 89%

“…x = 1.7 or 2.4 can also be discussed in terms of the higher colloidal stability of monomer polymer particles at higher level of emulsifier [12,28,[31][32][33]. The increased stability of the polymer particles may mainly result from the chemically bound molecules of Tw per 20 at the particle surface.…”

Section: Colloidal Parametersmentioning

confidence: 99%

“…0.2) at ca. 30-40% conversion results from the polymerization proceeding under the monomer-starved condition [12]. The accumulation of non-ionic emulsifier in the oil phase at high temperature initiates the formation of inverse micelles (water pools) in the monomer droplets which varies the colloidal stability of monomer droplets [12].…”

Section: Introductionmentioning

confidence: 99%

“…30-40% conversion results from the polymerization proceeding under the monomer-starved condition [12]. The accumulation of non-ionic emulsifier in the oil phase at high temperature initiates the formation of inverse micelles (water pools) in the monomer droplets which varies the colloidal stability of monomer droplets [12]. The depressed monomer droplet degradation can be related with the decreased amount of monomer and emulsifier in the aqueous phase available for the generation of particles by micellar or homogeneous nucleation.…”

Section: Introductionmentioning

confidence: 99%

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Miniemulsion Polymerization of Styrene Initiated by Tween-surfinit

Capek

2010

Designed Monomers and Polymers

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The sterically-stabilized miniemulsion polymerization of styrene initiated by peroxide-containing Tweens (Tw per , surfinit) was investigated. The conversion curves for miniemulsion emulsion polymerization are concave downward throughout the polymerization and the observed limiting conversions are much below 100% conversion. The polymerization rate vs conversion curve is described by a curve with two rate intervals and rate maximum located at low conversion. The consumption of peroxide groups in Tween (Tw per ), including their immobilization and accumulation into micelles, leads to the dead-end polymerization. The maximal polymerization rate increases with increasing the emulsifier and peroxide concentrations. The particle size decreases and the number of particles increases with increasing the concentration of emulsifier, Tw per and reducing agent. The increased stability of the polymer dispersions is attributed to the chemically bound moieties of Tw per to the particle surface. The values of the ratio of the final number of polymer particles to the initial number of monomer droplets (N p /N d ) favor the mixed mode of particle nucleation.

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Section: Rate Of Polymerizationsupporting

confidence: 89%

Section: Colloidal Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Miniemulsion Polymerization of Styrene Initiated by Tween-surfinit

Capek

2010

Designed Monomers and Polymers

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“…Under the current reaction conditions, solubility of the emulsifier in the monomer phase is relatively high. 24 The monomer-soluble emulsifier decreases the average monomer concentration at the reaction loci and promotes the chain transfer to emulsifier. 25 The accumulation of emulsifier in the monomer droplets is expected to decrease the rate of polymerization with conversion.…”

Section: Kinetic Parametersmentioning

confidence: 99%

Microemulsion Polymerization of Alkyl (Meth)acrylates Initiated by UV Light

Capek

1999

Polym J

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ABSTRACT:Radical polymerizations of polar unsaturated monomers ethyl acrylate, methyl methacrylate and nonyl methacrylate in an o/w microemulsion photoinitiated by a UV light were investigated. Polymerizations were conducted at low temperature to follow the effects of a varied solubility of monomer (coemulsifier) and/or diffusional degradation of monomer droplets on the kinetic and colloidal parameters. The rate versus conversion curve showed four regions with two rate maxima ca. at 5% to 20% and 50 to 70% conversion. The first rate maximum results from abrupt decrease of the monomer concentration at microemulsion loci and the second one from the increased accumulation of radicals in the latex particles. The higher polymerization rate of ethyl acrylate compared to that for methyl methacrylate or nonyl methacrylate was attributed to higher monomer concentration at reaction loci and propagation rate constant and lower quenching rate. The rate of polymerization was found to increase with incident light intensity and was most pronounced with nonyl methacrylate. The reaction order (the dependence of the rate of polymerization or the number of particles on the incident light intensity) was taken as a measure of particle nucleation efficiency. Particle size distribution was observed to be very narrow at low conversion and increased with increasing conversion.KEY WORDS Microemulsion j Polymerization I Alkyl (Meth)acrylates I Kinetics I Particle I Nucleation/ Microemulsion and miniemulsion polymerizations offer convenient access to well-defined microlatex particles being typically one order of magnitude smaller than polymer particles obtained by conventional emulsion polymerization. The fine monomer emulsion exhibits a large interface between monomer droplets and the aqueous phase. Under such conditions, continuous nucleation up to (very) high conversion is operative. There is no apparent constant rate period in the o/w microemulsion or miniemulsion polymerization. 1 -3 Ugelstadt et a/. 4 clearly demonstrated that monomer droplets could effectively compete with monomer-swollen micelles for capture of free radicals generated in the aqueous phase when the total surface area of the droplets became large enough. In conventional emulsion polymerization, the principle locus of particle nucleation is the aqueous phase or the monomer swollen micelles depending on the degree of water solubility of the monomers, an initiator and amount of emulsifier. Monomer droplets are considered only as monomer reservoir supplying monomer to the growing polymer particles. However, the small size of the monomer droplets (micro-or minidroplets) enables them to become the principle locus of particle nucleation ..The principle behind the formation ofmicroemulsions (droplet size I 0-50 nm) is penetration of coemulsifier into the water/oil interface, thereby decreasing surface tension and increasing interface area. Coemulsifier also decreases the rigidity of interface film due to increasing the molecular disorder. Coemulsifier promotes the formatio...

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Polymeric Nanoparticles

2017

Design of Nanostructures

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Emulsion polymerization of styrene: double emulsion effect

Cited by 19 publications

References 28 publications

Miniemulsion Polymerization of Styrene Initiated by Tween-surfinit

Miniemulsion Polymerization of Styrene Initiated by Tween-surfinit

Microemulsion Polymerization of Alkyl (Meth)acrylates Initiated by UV Light

Polymeric Nanoparticles

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